Spanner wrenches of various forms and configurations have been in use for many years. They have proven to be especially useful in applications where traditional open or closed wrenches, crescent wrenches, pliers and the like cannot be useful due to interference from nearby structures or the need for the application of extremely high levels of torque to the associated mechanical fastening device. Frequently, spanner wrenches are designed for a specific application, such as applying torque axially to a mechanical fastening device located in a restricted area such as a blind cavity, where conventional tools cannot be applied.
A major shortcoming of historical spanner wrench designs arises from their tendency toward special applications. Artisans and tradesmen were required to acquire a spanner wrench for each applications and distinct fastener size that he may encounter. Thus, over time they will be obligated to incur substantial costs as well as maintain a large and bulky tool collection.
Producers of industrial power tools, such as hand grinders employing consumable aggregate grinding wheels frequently employ spanner nuts for specialized applications. A prime example is the retention of grinding and cut-off wheels, which, by their nature, must be regularly replaced. As a result, the power tool producers are obligated to provide equally specialized spanner wrenches as an adjunct to the power tools. These spanner tools are prone to loss, damage and wear. Power tools designed for mass merchandizing to the general public similarly employ specialty spanner tools. But in their case frequently suffer from poor design and quality as the manufacturer focuses on low cost processes. In both cases, a lost, worn or defective tool can destroy the utility of an expensive power tool. Lastly, replacement spanner tools can be difficult to obtain inasmuch as they are frequently produced by only a single manufacturer.
The forgoing problems have been partially overcome by various improvements over the years. For example, there are several adjustable spanner wrenches described in the patent literature which provide an adjustable span between slots in a mechanical fastening device.
U.S. Pat. No. 2,803,981, shows a spanner wrench in which a pivotally mounted bar at the base of the wrench has a slot wherein drive pins are mounted. The span between the drive pins is adjusted by moving the drive pins within the slots and the drive pins are tightened at a desired position by nuts mounted on a threaded upper portion of the drive pin. The spanner wrench according to the '981 patent has the disadvantage that as the tightening nuts become loosened, the drive pins slide along the slots and it is difficult to maintain the proper spacing. Also, with wear, the drive pins would tend to slide in the slots, thus limiting the usefulness of the wrench. Further, the range of adjustment is limited to twice the length of the slot.
Another adjustable spanner wrench is described in U.S. Pat. No. 3,010,347, in which the L-shaped members are attached to the movable and fixed jaws of a crescent wrench. Adjustment of spacing is made by opening or closing the jaws of the crescent wrench. While the '347 patent shows a device which has a certain amount of flexibility, the handle of the crescent wrench must be relatively at a right angle to the axis about which the article is to be turned. In many applications where space is limited, such a wrench would not be usable.
Another adjustable spanner wrench in the prior art is illustrated in U.S. Pat. No. 3,731,560, which teaches of a wrench having a Y-shaped handle wherein each of the branches of the Y had a hole therein to accept a disc which is rotatably mounted in the hole and wherein the disc has a drive pin mounted near the edge of one face thereof An adjustable spanner wrench according to the '560 patent is limited to a range of adjustment which is equal to twice the diameter of the discs mounted in the holes the Y-shaped handle. Also, as above, the handle must be at a right angle to the article, which is to be turned.
Still another adjustable spanner wrench is disclosed in U.S. Pat. No. 4,210,037. The '037 patent represents an improvement over the design of the '560 patent, but suffers from many of its shortcomings. The assemblies which effect the adjustability are difficult to adjust with substantial precision and inevitably tend to loosen during use promoting rapid wear. Furthermore, the long handles typically found on prior art spanner wrenches do not lend themselves to smaller scale applications.
Universal among the above described prior art spanner wrenches are their excessive specialization coupled with their lack of robust design suitable for application of large torque levels while affording great flexibility in downscaling and application in conjunction with other more common hand tools.
The present invention overcomes the forgoing difficulties of traditional spanner wrench designs by providing a spanner socket, which can be employed either by itself or with ubiquitous hand tools such as ratchets or wrenches as force multipliers. The invention further provides for adjustability of spacing as well as the number of drive pins, rendering a device well adaptable for many varied applications. Lastly, the invention facilitates the easy removal and replacement of worn drive pins and reconfiguration of the types and positioning of various pin sets.